The invention is related generally to shut-off valves for liquid suction systems and, more particularly, to shut-off valves for water suction systems for swimming pools, spas and the like. Still more particularly, this invention relates to rotary-plug shut-off valves for suction cleaning systems for swimming pools, spas and the like.
Liquid suction systems are employed in a variety of settings and for a variety of purposes. One example is the liquid suction systems which are used for swimming pools, spas and the like. Such a system typically includes a suction pump away from the pool which draws water from the pool at one or more suction ports located along the pool sidewall and/or through the main drain of the pool. A hose is typically connected to one of the sidewall ports and extends to an automatic swimming pool cleaner which draws pool water for cleaning purposes.
Typically, one or more valve mechanisms are used to determine whether water will be sucked from the pool through the main drain and/or through the side port(s). One example of such valve mechanisms is the three-way rotary-plug valve disclosed in U.S. Pat. No. 4,470,429 (Johnson). Such device is a manually-operated rotary-plug valve.
In swimming pool suction systems, when suction lines become obstructed with debris, damage to the lines and equipment may result if excessive vacuum pressures are not quickly released. Furthermore, a risk of bodily injury may exist if a vacuum or suction device comes into contact with a person. Various bypass devices have been developed to address problems of excessive vacuum due to blockage. One example is the device disclosed in U.S. Pat. No. 4,570,660 (Chauvier). Another is the automatic locking bypass valve which is disclosed in our copending U.S. patent application Ser. No. 09/327,913 (Rief et al.), filed Jun. 8, 1999.
Valve mechanisms of the prior art for controlling which lines will be open to vacuum forces, such as the rotary-plug valve of the aforementioned Johnson patent, have various shortcomings. Among these are the fact that they require manual operation, and thus fail to address problems associated with unexpected line clogging or blockage. Also, even when operated manually such devices fail to provide any vacuum relief in a line which has been manually shut off because of line blockage. In such cases, it may become necessary to turn off the pump and reopen the line in order to relieve the vacuum force remaining in the line. Furthermore, while such devices can be locked into a predetermined position, such locking requires an additional manual step, beyond merely closing a line.
The prior art fails to disclose or suggest a rotary-plug shut-off valve which overcomes these problems and shortcomings.
It is an object of this invention to provide an improved rotary-plug shut-off valve overcoming some of the problems and shortcomings of the prior art.
Another object of this invention to provide an improved rotary-plug shut-off valve which can operate automatically, i.e., which automatically shuts off a line when vacuum pressure in such line exceeds a predetermined acceptable range of vacuum pressures.
Another object of this invention is to provide an improved rotary-plug shut-off valve which automatically locks in a shut-off position in response to unacceptable line pressures.
Another object of the invention is to provide an improved rotary-plug shut-off valve which automatically relieves the vacuum pressure in a closed line after such line has been shut off.
Yet another object of the invention is to provide a rotary-plug shut-off valve which shuts off a flow line due to unacceptable vacuum pressure therein due to blockage and simultaneously relieves the unacceptable vacuum pressure in the line upon line shut-off.
Another object of the invention is to provide an improved rotary-plug shut-off valve which, although it automatically shuts off a line and automatically relieves line pressure, has a override for manual operation and resetting.
Still another object of the invention is to provide an improved automatic rotary-plug shut-off valve mechanism which can be used to retrofit a standard rotary-plug shut-off valve.
Another object of the invention is to provide an improved rotary-plug shut-off valve which is simple in construction and easily maintained.
These and other objects of the invention will be apparent from the following descriptions and from the drawings.
This invention is an improved shut-off valve for use in liquid suction systems. More specifically, this invention is an improved rotary-plug shut-off valve of the type including a multi-port valve body forming a valve chamber and having an outlet and first and second inlets, a rotary plug in the valve chamber, and an actuator to turn the plug. The improvement of this invention overcomes the aforementioned problems and shortcomings of the prior art; it is an improved shut-off valve which satisfies the objects of the invention set forth above.
The improved shut-off valve of this invention includes as its principal elements: an actuator housing; a base member; a vacuum-reactive member; a spring; and a piston. The actuator housing is affixed to the valve body adjacent to the plug, and forms an actuator chamber which is in fluid communication with the valve chamber, e.g., through openings in the base member. The base member is affixed to the actuator housing in position to form one end of the actuator chamber. The base member also forms (1) a sleeve through which a portion of the piston extends, (2) a guide which engages a portion of the piston, as hereafter explained, and (3) a first spring-abutment. The vacuum-reactive member is located within the actuator chamber and is movable toward and away from the base member, along the axis of the actuator chamber. The vacuum-reactive member also forms a second spring-abutment which is opposed to the first spring-abutment.
The aforementioned spring is in axial compression and rotational tension between the first and second spring-abutments and is compressible by vacuum force on the vacuum-reactive member. The spring, which is preferably in the form of a coiled helix, serves at the proper time to provide the turning force necessary to move the rotary plug from a position covering one inlet to the valve chamber to a position closing the other inlet to the valve chamber. As hereafter explained, the spring moves the rotary plug by acting through the vacuum-reactive member and the piston.
The piston is affixed to the vacuum-reactive member and is rotationally aligned with the plug. The piston includes a shaft which extends through the sleeve. The piston also includes an anti-rotation structure which is: (a) slidably engaged with the guide (portion of the base member) in one rotational alignment therewith when in a normal operating range of axial positions with respect theretoxe2x80x94i.e., when the piston anti-rotation structure and the guide (of the base member) are within a normal operating range of relative axial positions; and (b) out of sliding engagement with the guide beyond such normal operating range of relative axial positionsxe2x80x94i.e., when the piston anti-rotation structure and the guide (of the base member) are within a normal operating range of relative axial positions.
Given these parts and relationships, when the anti-rotation structure of the piston is out of sliding engagement with the guide, and thus free to rotate, the spring rotates the vacuum-reactive member and piston. This rotation of the piston causes the plug to rotate, under the uncoiling pressure of the spring, from one inlet to the other inlet.
In highly preferred embodiments, the first and second inlets are at the ends of first and second inlet lines extending to the valve chamber, and a vacuum-relief line extends from one of the inlet lines, at a position upstream of the valve chamber, to atmosphere and a vacuum-relief valve is located in such vacuum-relief line. It is highly preferred in such embodiments to have linkage between the actuator structure and the vacuum-relief valve in order that the vacuum-relief valve is opened upon rotation of the plugxe2x80x94i.e., upon the shutting off of such line, referred to herein as the protected line. Such automatic relief of residual vacuum pressure, remaining in the protected line upon automatic shut-off, is an important feature of this invention.
In highly preferred embodiments of this type, the vacuum-relief valve includes a valve head and a stem attached to it, and the aforesaid linkage includes a transfer member which has proximal and distal end portions, the proximal end portion being engaged with the vacuum-reactive member and the distal end portion being engaged with the valve stem. Most preferably, the proximal end portion of the transfer member is in rotational alignment and slidable engagement with the vacuum-reactive member along the axis thereof. And, in highly preferred embodiments, the valve stem preferably has an aperture through it to receive the distal end of the transfer member, which is in the form of a rod that is axially offset from the axis of the vacuum-reactive member. Thus, when the vacuum-reactive member rotates, the transfer member also rotates, and, because it is an off-axis distal rod which is in the valve stem aperture, rotation of the transfer member moves the valve stem (i.e., along its own axis) to operate the vacuum-relief valve.
A vacuum-relief housing is preferably attached to the actuator housing and serves to house the transfer member and the vacuum-relief valve. Such vacuum-relief housing also forms a valve seat for the vacuum-relief valve, forms air intake vents to atmosphere, and also supports the valve stem.
It is highly preferred that a reset/override lever be attached to the transfer member to facilitate manual resetting of the rotary-plug shut-off valve. Such lever serves to manually reset the rotary-plug shut-off valve to again open the protected line for flow vacuum-initiated flow. Furthermore, such lever can be used to intentionally close the protected line whenever that is desired.
Referring again to those elements of the inventive rotary-plug shut-off valve which are within the actuator chamber and/or the valve chamber, it is highly preferred that the rotary plug and the piston have first and second non-rotational mating surfaces, respectively, i.e., mating surfaces which hold the piston and the plug in fixed rotational orientation with respect to one anotherxe2x80x94at least when the anti-rotation structure of the piston is out of sliding engagement with the guide of the base member such that rotation of the piston rotates the rotary plug.
In the most preferred of such embodiments, the first non-rotational mating surface is a piston-mating surface on the plug which is outside the actuator chamber. The piston has a piston head, also outside the actuator chamber, and the second non-rotational mating surface is a plug-mating surface on the piston head, such plug-mating surface being configured to engage the piston-mating surface of the plug. Such mating engagement causes rotation of the piston to rotate the plug.
One alternative arrangement of the first and second non-rotational mating surfaces of the rotary plug and piston, respectively, involves a rotary-plug shaft which extends slidably into a cavity within the piston shaft. In such embodiments (not illustrated herein), the rotary-plug shaft and the cavity into which it extends are non-circular in cross-section, such that turning of the piston, when it is can occur, also turns the rotary plug. In such embodiment, the non-rotational mating (to allow rotation of the piston) exists at all times, not simply when the aforementioned anti-rotation structure of the piston is out of sliding engagement with the guide of the base member.
In certain highly preferred embodiments, the anti-rotation structure of the piston mentioned earlier herein involves other structures of the piston head, which is outside the actuator chamber, and characteristics of the guide (i.e., characteristics of the fixed-position base member). More specifically, the guide of the fixed position base member faces the valve chamber and is shaped to receive and hold the piston head in the aforesaid one rotational alignment therewith; the outside edge (perimeter) of the piston head is configured to mate with the guide.
When the piston, and thus the piston head, are moved axially, whether by the application of vacuum pressure on the vacuum-reactive surface or by depression of the vacuum-reactive surface and piston by depression of the manual reset/override lever, and the piston-head movement causes it to slide beyond (i.e., out of) its non-rotational engagement with the guide, then the rotational tension of the spring causes the vacuum-reactive surface and the piston head to quickly and firmly rotate, preferably about 90xc2x0. And, as already noted, this causes rotation of the rotary plug.
Most preferably, the preferred form of non-rotational engagement of the piston head and the base-member guide are combined with the preferred form of the piston with the rotary plug. That is, as earlier described herein, the piston head and the plug have plug-mating and piston-mating surfaces, respectively, to hold the piston and the plug in fixed rotational orientation so that rotation of the piston rotates the plug.
In somewhat broader terms, the rotary-plug shut-off valve of this invention includes: an actuator housing affixed to the valve body adjacent to the plug and forming an actuator chamber communicating with the valve chamber; a base member attached to the actuator housing in fixed axial position and forming (a) an end of the actuator chamber, (b) a sleeve, (c) a guide, and (d) a first spring-abutment; a vacuum-reactive member within the actuator chamber, movable toward and away from the base member, and supported by spring pressure at a position away from the base member such that it is movable toward the base member by sufficient vacuum force on the vacuum-reactive member; a piston attached to the vacuum-reactive member, rotationally aligned with the plug, and having a (a) shaft extending through the sleeve and (b) an anti-rotation structure which is (1) slidably engaged with the guide in one rotational alignment therewith in a normal operating range of axial positions with respect thereto and (2) out of sliding engagement with the guide beyond such normal operating range; and a spring in rotational tension positioned and secured to rotate at least the piston and thereby rotate the plug from one inlet to the other inlet when the piston anti-rotation structure is out of sliding engagement with the guide.
While a specific single spring was referred to above and is illustrated herein, a variety of other spring arrangements are possible to provide (1) the necessary spring pressure to resist vacuum-induced movement of the vacuum-reactive member and (2) the necessary torsional force to rotate parts when necessary. For example, one or more springs in compression can be used to resist the vacuum-induced movement of the vacuum-reactive member, while another spring could be used to provide torsional force. The single spring referred above is highly preferred and advantageous.
In still broader terms, the rotary-plug shut-off valve of this invention includes: an actuator housing affixed to the valve body adjacent to the plug; a vacuum-sensing-and-reacting device secured with respect to the actuator housing and in communication with the valve chamber; an actuator in the actuator housing, engageable with the rotary plug, and linked for control to the vacuum-sensing-and-reacting device thereby to rotate the plug from one inlet to the other inlet when the vacuum-sensing-and-reacting device senses excessive vacuum; a vacuum-relief line extending from the first inlet line to atmosphere; and a vacuum-relief valve in the vacuum-relief line.
Preferred embodiments of such rotary-plug shut-off valve were described in some detail above. One alternative embodiment involves placement of a vacuum sensor in the valve chamber, such vacuum sensor being set at a predetermined pressure level to initiate the actuator. The actuator may be in the form of an electric motor within the actuator housing. As in other embodiments described above, the vacuum-relief valve in an embodiment relying on sensors, motors, and the like, will be actuated simultaneously with actuation of the rotary plug. A variety of actuating and control mechanisms, including programmable controllers, can be used without departing from the spirit of this invention.
The improved rotary-plug shut-off valve of the present invention is particularly well adapted for use in a liquid suction system for swimming pools, spas and the like, particularly those in which automatic pool cleaners are used. However, applications of the invention are not limited to such applications.